Custom header support for "provider"

[lizdeika]

Hi, It would be perfect to have custom headers' support in airbyte terraform provider. The headers should be yielded to the server_url when doing requests. This would help terraforming protected airbyte instances where Basic Auth is not an option(for various reasons).

What do you think?

Example:

provider "airbyte" {
  password = ""
  username = ""

  server_url = "https://protected.airbyte-instance.company.url"

  header {
    name  = "X-Some-Header"
    value = "SomeValue"
  }

  header {
    name  = "X-Other-Header"
    value = "OtherValue"
  }

  header {
    name  = "T-Custom-Header"
    value = "CustomValue"
  }  
}

Thank you